Speed Controller - Siemens SINAMICS S120 Function Manual

Vector control

5.3 Speed controller

5.3 Speed controller
Both closed-loop control procedures with and without an encoder (VC, SLVC) have the same
speed controller structure which contains the following components:
● PI controller
● Speed controller precontrol
● Droop
The total of the output variables result in the torque setpoint which is reduced to the
permissible magnitude by means of the torque setpoint limitation.
Function of the speed controller
The speed controller receives its setpoint (r0062) from the setpoint channel and its actual
value (r0063) either directly from the speed sensor (control with sensor (VC)) or indirectly via
the motor model (control without sensor (SLVC)). The system deviation is increased by the
PI controller and, in conjunction with the precontrol, results in the torque setpoint.
When the load torque increases, the speed setpoint is reduced proportionately when droop
is active, which means that the single drive within a group (two or more mechanically
connected motors) is relieved when the torque becomes too large.
Figure 5-6
The optimum speed controller setting can be determined via the automatic speed controller
tuning function (p1900 = 1, rotating measurement).
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Speed controller
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
Drive functions